ServerTransaction serverTransaction = requestEvent.getServerTransaction();
if(serverTransaction==null){
serverTransaction = sipProvider.getNewServerTransaction(requestEvent.getRequest());
}
Response responseRing = messageFactory.createResponse(Response.RINGING, requestEvent.getRequest());
responseRing.addHeader(contactHeader);
serverTransaction.sendResponse(responseRing);
//System.out.println("Ringing sent");
//System.out.println("Ringing sent");
Response responseOk = messageFactory.createResponse(Response.OK, requestEvent.getRequest());
responseOk.addHeader(contactHeader);